Heli-Max HMXM1012 - Manual (Page 2)

❏ 13. Install a servo arm onto the tail rotor servo. Please note
the current position of the arm and move the tail rotor stick full
left. Hold for one second and allow the control stick to re-center.
If the servo returns to center every time, then you are in non-
heading lock mode which is what we require to continue with
the setup. Please move onto the next step. If the servo does
not return to center, then you are in heading lock mode. Please
change the gyro gain switch on the transmitter and re-test until
the servo re-centers every time.
❏ 14. Now that we know the gyro is in normal mode we need
to position the servo arm properly. Remove the servo arm
and place it onto the servo so that the arm is perpendicular or
parallel to the servo. Most servos use an odd number of splines
so it is possible to achieve different mounting positions by simply
rotating the arm by 90º intervals. Once you have found the best
mounting position, remove the unused sides of the arm.
❏ 15. Mount a control ball onto the servo arm 7.5mm from
center. Apply thread locking compound to the screw and nut.
Reinstall the servo arm mounting screw.
❏ 16. Our goal is to have maximum mechanical throw without
any binding. The fi rst step is to verify centering and throw limits
for the gyro, servo, and helicopter. Move the tail rotor stick full left
on the transmitter and hold the tail rotor pushrod ball link over
the control ball on the tail rotor servo. Now perform the same
thing using full right tail rotor. Evaluate the alignment and throw
and make any length adjustments necessary to the t/r pushrod.
Once you have the throw centered, if you have determined that
the pushrod is not traveling far enough, simply move the control
ball one hole out from center on the servo arm. If you have
determined that less throw is needed simply move the control
ball in one hole towards center on the servo arm.
❏ 17. Apply full right tail rotor and verify that the tail rotor will
cause the nose of the helicopter to move to the right. If you
have trouble trying to determine which direction the tail rotor
operates for left and right, please refer to the helicopter’s
instruction manual.
❏ 18. Pick the helicopter up by the main shaft with the nose
facing away from you. Now rotate the nose of the helicopter to
the left (counter clockwise). While doing this verify that the gyro
compensates in the correct direction. In this example the gyro
would apply right tail rotor (clockwise) to compensate for the
helicopter rotating to the left (counter clockwise).
❏ 19. Set the gain to 45% heading lock mode. Set any secondary
gain %’s to 45% heading lock mode at this time. Later on you
can make adjustments as necessary.
❏ 20. The ATV or End Point function within your transmitter will
control the maximum pirouette rate. The ATV and End Point
functions in the transmitter have no control over how far the tail
rotor servo will travel. If you are having any binding problems
in the tail rotor linkage, then you must adjust the control ball
location on the servo arm instead. Set the ATV or End Points for
the Tail Rotor channel (Rudder – typically channel 4 for Futaba)
to 70% for left and right directions. This will reduce the pirouette
rate to a reasonable level for your fi rst fl ights. If you feel that the
pirouette rate is slow after the fi rst test fl ight, then increase the
ATV or End Point values until you have achieved a setting you
like. If you feel the pirouette rate is too quick, then reduce the
ATV or End Point values.
❏ 21. Exponential should be used on the transmitter to help
soften the feel of the tail rotor stick. On a Futaba transmitter
use − 40% Expo to start with (typically this is channel 4 on
Futaba transmitters).
❏ 22. Please review your work and ensure all connectors
are fi rmly plugged in. Verify that the gyro compensates in the
correct direction and the tail rotor servo is responding in the
correct direction.
❏ 23. Disconnect the power from the helicopter for 30 seconds.
Re-connect the power, allowing 7–10 seconds for the gyro
to initialize. Once the gyro has initialized, the tail rotor servo
should center and remain there. If you notice any slow drifting
in the tail rotor servo, please try to trim this out using the tail
rotor trim. During the initial fl ight you may have to make some
minor trim adjustments.
❏ 24. Your gyro is now setup and ready to fl y. Heading Lock
mode operates completely different than normal rate gyros.
Once you place the model on the ground, you must center the
tail rotor pitch slider before starting to spool the blades up. You
will have to make some small corrections as the model begins
to lift off. Once the helicopter is in the air the gyro will hold the
tail at all times unless you make an input. If this is the fi rst time
you have fl own a Heading Lock gyro, please be patient during
the fi rst few test fl ights until you have become accustomed to
the new gyro.
GAIN ADJUSTMENTS
Start with the recommended gain setting of 45% and slowly
increase the % until the tail starts to oscillate (wag) during fl ight.
When using a heading lock gyro it is not necessary to run the
highest gain possible. Typically you will fi nd the gyro works the
best around 3%–5% lower than the maximum gain you can run.
Once you have found what you believe is the ideal gain setting,
try adding and subtracting 3% to see if operation improves.
Finding the ideal gain setting will take some experimentation.
If the gyro is allowing the tail to drift then raise the gain % and
test fl y the model.
If the tail is quickly oscillating (wagging), then lower the gain %
and test fl y the model.
TROUBLESHOOTING
The gyro indicator light does not come on. Make sure the
rudder and gyro gain control leads are plugged into the receiver
and verify the polarity of the connections. Verify that the servos
connected to the receiver operater.
I cannot control the tail rotor after takeoff. Verify that the
gyro compensation direction is correct and that the drive system
and linkages to the tail rotor are in proper working condition.
The models spins out of control after lift off. Verify that the
gyro compensation direction is correct. If the compensation
direction is incorrect, the model will spin uncontrollably.
The trim changes constantly in fl ight. Verify that there are no
issues in the tail rotor drive system and the pitch control linkage.
Extreme heat near the gyro may cause some drift. Vibration will
cause the trim to shift and erratic operation of the gyro. If you
notice any vibrations in the mechanics, please address that
issue fi rst.
© Copyright 2008 HMXM1012Mnl V1.0